<font face="楷体_gb2312" color="blue">
    <?php
    echo "圆周率的三种书写方法：<p>";
    echo "第有一种 ：pi()=".pi()."<p>";
    echo "第二种：3.14159265359= ",3.14159265359,"<p>";
    echo "第三种：314159265359E-11=",314159265359E-11,"<P>";

?>
</font>